yeah, if he's got the np435 then he's got a granny low.. 6.69 ratio.. plus 4.10s in the axle..
i'm not good with all the math that goes into this, but i do know that you're significantly heavier and a powerstroke should outpull a 350 any day
i just looked at your mods, you should take him, your bigger tires give you a significant advantage. also just be aware if he has lockers he'll have all 4 tires pulling. so be careful about that, though 38's vs 35s you should be fine